1. Field of the Invention
The present invention relates to a cutting apparatus for ceramic green bodies, which are soft and easily deformable, such as formed bodies of ceramic honeycomb structural bodies.
2. Description of Related Art
Generally, as a cutting apparatus for cutting the ceramic green bodies such as ceramic honeycomb structural bodies, the cutting apparatuses having various constructions have been known. As an example, the applicant disclosed, in JP-B-4-60402 (U.S. Pat. No. 4,702,138), the cutting apparatus for ceramic green honeycomb structural bodies in which generations of deformation and fracture of the ceramic green honeycomb structural bodies can be prevented by using xe2x80x9cdraw-cutxe2x80x9d operation.
FIG. 9 is a schematic view showing the cutting apparatus for ceramic green honeycomb structural bodies mentioned above which have been proposed previously by the applicant. In the embodiment shown in FIG. 9, a cutting apparatus 51 has a following construction. Two arms 53-1 and 53-2 are arranged in a widthwise direction of a ceramic green honeycomb structural body 52. A fine wire 54 used for a cutting operation is extended between the arms 53-1 and 53-2 via rollers 55 arranged to the arms 53-1 and 53-2, and ends of the fine wire 54 extended between the two rollers 55 is cut into the ceramic green honeycomb structural body 52, while the arms 53-1 and 53-2 are moved in a cutting direction of the ceramic green honeycomb structural body 52 by means of an arm moving mechanism (not shown). When the arms 53-1 and 53-2 are moved in the cutting direction of the ceramic green honeycomb structural body 52 and the fine wire 54 for the cutting operation cuts the ceramic green honeycomb structural body 52, at least one operation such that the fine wire 54 is pulled toward one roller 55 side and then pulled toward the other roller 55 side is performed by a fine wire reciprocating mechanism 57.
In the cutting apparatus mentioned above, it is possible to cut rapidly the soft and easily otherwise deformed body such as a ceramic green body without deformation. However, since, in the case of cutting the ceramic green body, a portion of the fine wire 54 used for cutting is always same, there is a drawback such that a life of the fine wire 54 is short and thus it is necessary to exchange the fine wire 54 frequently. Moreover, since there is a portion for connecting the spring 56 and the fine wire 54 and further since it is necessary to extend the fine wire 54 via a plurality of rollers 55, there is a drawback such that an exchanging operation of the fine wire 54 is troublesome.
An object of the invention is to eliminate the drawbacks mentioned above and to provide a cutting apparatus for ceramic green bodies in which an exchanging interval of a fine wire for cutting can be long so that a life of the fine wire can be long and in which an exchanging operation of the fine wire is easy.
According to the invention, a cutting apparatus for cutting ceramic green bodies comprising; a travelling path for travelling a ceramic green body; supporting beds for supporting the ceramic green body arranged on the travelling path with a constant interval; a pair of first arm and second arm arranged movably in a travelling direction of the ceramic green body, which are provided at both side ends of the travelling path, a first drive portion and a second drive portion for moving the first arm and the second arm respectively upward or downward, which are provided to the first arm and the second arm respectively; a fine wire for cutting the ceramic green body extended between the first arm and the second arm; a first fine wire supporting portion and a second fine wire supporting portion for moving the fine wire for cutting the ceramic green body from one side to the other under constant tension, when the fine wire traverses the ceramic green body by moving the first and second arms in a cutting direction of the ceramic green body. The arms are driven by the first and second drive portions; and a third drive portion for moving the first and second arms in the same direction as the travelling direction of the ceramic green body.
In the present invention, the first fine wire supporting portion and a second fine wire supporting portion function to move the fine wire for cutting the ceramic green body, which extends between the first arm and the second arm, from one side to the other under constant tension. Therefore, when the fine wire traverses the ceramic green body by moving the first and second arms in a cutting direction of the ceramic green body, which are driven by the first and second drive portions, a portion of the fine wire used for cutting differs so that such a portion of the fine wire is used only for a few cutting operations at most, and the fine wire is not broken during the cutting operation. By utilizing preferable following techniques such as (1) the cutting operation is performed by moving the fine wire for cutting the ceramic green body from one side to the other side of the first and second arms, (2), in the case of (1) mentioned above, a moving direction of the fine wire from one side to the other side is reversed every cutting operations, (3) the cutting operation is performed by moving the fine wire reciprocally in both directions, and (4), in the cases of (1)-(3) mentioned above, a travelling speed of the fine wire is changed between travelling from the first arm to the second arm and travelling from the second arm to the first arm. In this manner, it is possible to achieve a long life of the fine wire.
Moreover, in the preferred embodiment, the first and second fine wire supporting portions comprise; a first and second servo motor arranged respectively to the first and second arms; a first and second magnet member arranged around respective rotation axes of the first and second servo motors; and a first and second bobbin for rewinding the fine wire for cutting the ceramic green body. It is easy to construct the cutting apparatus in such a manner that, in the case that the fine wire for cutting the ceramic green body is completely rewound from one bobbin (first bobbin or second bobbin) to the other bobbin (second bobbin or first bobbin), the first bobbin and the second bobbin are exchanged to previously prepared new first bobbin and second bobbin in which the fine wire is extended between them and is completely rewound to one bobbin. In this case, it is possible to perform the fine wire exchanging operation easily.
Further, in the preferred embodiment, a first traversing mechanism and a second traversing mechanism for varying a rewinding position in respective first and second bobbins, in the case that the fine wire for cutting the ceramic green bodies is to be rewound to the first and second bobbins, are provided respectively to the first and second arms. It is possible to prevent a friction increase due to an intertwisting between fine wires when the fine wire is to be rewound around the first bobbin or the second bobbin, and it is also possible to align the fine wires in the first bobbin or the second bobbin. In this case, it is possible to prevent a breakage of the fine wire.